原始ajax例子
    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
  <head>
    <title>原始ajax例子</title>
  </head>
  <body>
  	<button id="btnajax">ajax调用</button>
  	<br/>
  	<div id="divResult"></div>
  	<script type="text/javascript">
  		//跨浏览器获取xmlhttpRequest对象
  		function AjaxXhttpRequest(){
  			var xmlHttp;
  			try{
  				xmlHttp = new XMLHttpRequest();  				
  			}
  			catch(e){
  				try{
  					xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
  				}
  				catch(e){	
	  					try{
	  						xmlHttp = new ActiveXObject("Microsoft.MXLHTTP");	  						
	  					}
	  					catch(e){
	  						alert("您的浏览器不支持AJAX!");
	  						return false;
	  					}  				
  					}
  			}
  			return xmlHttp;
  		}
  		//使用XMLHttpRequest对象发送请求
  		var xhr = newAjaxXmlHttpRequest();
  		document.getElementById("btnajax").onclick = function(){
  			var xhr = new AjaxXmlHttpRequest();
  			xhr.onreadystatechange = function(){
  				if(xhr.readyState == 4){
  					document.getElementById("divResult").innerHTML = xhr.responseTest;
  				}
  			}
  			xhr.open("GET","../data/AjaxGetCityInfo.aspx?resultType = html",true);
  			xhr.send(null);
  		}
  	</script>
  </body>
</html>